5. Patients may not receive Coumadin while on study. Patients may receive low molecular weight heparin or novel oral anticoagulants (eg. dabigatran, apixaban, rivaroxaban) provided that the dose is held 1-2 days before injections are given and biopsies are performed per the protocol. Anti-platelet agents and herbal substances are allowed at the discretion of the treating endoscopist.